What if the coup occurred in 1940?Unless the British Empire has somehow collapsed, then any Boer coup in South Africa will be crushed. Even if the British Empire has collapsed, then South African Anglos, British Rhodesians, and loyalist Boers will likely put down the coup.
Then it would still be crushed, but it would just take longer. South Africa is too far away to receive support from the Axis. There would be serious effects on the future of South Africa though. Britain might feel the need to "supervise" South Africa a lot more, preventing apartheid. J. B. M. Hertzog and Jan Smuts are likely to be targets for assassination, would could have major effects on South African politics. Maybe @Marius could give you more information.What if the coup occurred in 1940?
Then it would still be crushed, but it would just take longer. South Africa is too far away to receive support from the Axis. There would be serious effects on the future of South Africa though. Britain might feel the need to "supervise" South Africa a lot more, preventing apartheid. J. B. M. Hertzog and Jan Smuts are likely to be targets for assassination, would could have major effects on South African politics. Maybe @Marius could give you more information.